Equine airway disease is a prominent disease in many horses. It can be divided into the diseases of the upper and lower airways. There are a number of equine lower airway diseases with noninfectious origin such as RAO (or heaves or equine chronic obstructive pulmonary disease), IAD, SPAOPD and exercise induced pulmonary hemorrhage (EIPH). The latter is typically diagnosed in racehorses. RAO, IAD and SPAOPD are diseases with an allergic background. Rarely diagnosed additional lower airway disorders are granulomatous, neoplastic and interstitial pneumonias. The infectious diseases of the lower airway include bronchitis, pneumonia, pleuritis or a combination of these caused by viral, bacterial, fungal and parasitic agents (Kutasi et al., 2011).
Common phenotypic manifestations of airway disease in horses include coughing, nasal discharge, increased respiratory effort and poor performance or exercise intolerance. Additionally, fever, depression, decreased appetite and weight loss can be observed in infectious airway diseases (Couetil et al., 2007 and Kutasi et al., 2011).
Equine airway diseases with an allergic background cannot be cured but only kept asymptomatic. The known therapies for these horses include changes in the environment and the administration of different drugs. The aim of the change in the stable environment is to improve airway quality and to reduce the allergen exposure of the horses, which might trigger the exacerbations of RAO, SPAOPD and IAD. The following drugs are used for the treatment of airway diseases with non-infectious origin: glucocorticoids, bronchodilators (beta-2 adrenoceptor agonists and muscarinic antagonists), and mucosolvants (dembrexin and acetylcystein). In addition, antibiotics are administered for infectious airway diseases. Prominent side effects of these standard therapies are tachycardia, mydriasis, change in the hydration status of the mucous membranes and colic for bronchodilators and adrenocortical suppression (reduction in the blood serum levels of cortisol), laminitis, hepatopathy, muscle wasting, altered bone metabolism, increased susceptibility to infection (neutrophilia, lymphopenia) and decreased antibody response to vaccination for glucocorticoids (Couetil et al., 2007, Dauvillir et al., 2011).
The problem underlying the present invention is to provide a medication for horses which allows the treatment of airway disease in horses with a quick onset of action while reducing the risk of side effects for the treated animals.